Caption: Vitamin B2. Polarised light micrograph graphic of crystals of riboflavin, or vitamin B2. This vitamin forms these spiky water-soluble crystals. Vitamin B2 is essential for the activities of various enzymes involved in the breakdown of carbohydrates, fats, and proteins in the body. It is also part of a dietary growth factor, forming complexes with other b-group vitamins. Vitamin B2 is widely available in food sources such as liver, milk, egg white, brewer's yeast and whole grains. Deficiency of vitamin B2 may lead to anaemia, eye disorders such as amblyopia, and seborrhoeic dermatitis. An excess intake of this vitamin is not harmful.